Shear strength of ball studs according to the resistance welding conditions &amp; reliability testing based on the weibull distribution function

Park, In-Duck; Nam, Ki-Woo; Kang, Change-Yong

doi:10.1007/s12206-018-1111-y

Cited by 6 publications

(3 citation statements)

References 5 publications

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“…This can be seen that the hardness of the material does not have a constant value but a distribution. Characteristic of the hardness distribution can be explained by Weibull distribution (Weibull, 1951; Ahn et al , 2016, 2017; Park et al , 2018).…”

Section: Resultsmentioning

confidence: 99%

Failure analysis and countermeasures of the SCM435 high-tension bolt of three-step injection mold

Nam

Yun

2020

IJSI

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PurposeThe objective of this study was to perform damage analysis of SCM435 high-tension bolts connecting upper and lower parts of a three-stage injection molding machine.Design/methodology/approachDamage material used in this study was a SCM435 high-strength bolt connecting upper and lower molds of a three-stage injection mold. Causes of damage were determined by macroscopic observation. Microstructure observation was done using a metallic microscope, scanning electron microscope (SEM, S-2400, HiTachi, Japan), energy dispersive X-ray spectroscopy (EDS, Kevex Ltd., Sigma) and Vickers hardness tester (HV-114, Mitutoyo). Fatigue limit of the damaged material was evaluated using equivalent crack length.FindingsBolts were fractured by cyclic bending stress in the observation of ratchet marks and beach marks. The damaged specimen showed an acicular microstructure. Impurity was observed. Chromium carbide was observed near the crack origin. Both shape parameters of the Vickers hardness were similar. However, the scale parameter of the damaged specimen was about smaller than that of the as-received specimen. Much degradation occurred in the damaged specimen. Bolts should undergo accurate heat treatment to prevent the formation of chromium carbide. They must prevent the action of dynamic stresses. Bolts need accurate tightening and accuracy of heat treatment. Screws require compression residual stress due to peening.Originality/valueThis study conducted failure analysis of damaged SCM435 bolts connecting upper and lower parts of the three-stage injection mold. Fatigue limit of the damaged material was evaluated using equivalent crack length. In order to control this fracture, accurate tightening of bolts, accuracy of heat treatment and screws are required for compression residual stress due to peening.

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Section: Resultsmentioning

confidence: 99%

Failure analysis and countermeasures of the SCM435 high-tension bolt of three-step injection mold

Nam

Yun

2020

IJSI

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“…It is primarily used for applications with the appropriate degree of overall penetration that are critical to services. e automation system relies on accurate control of joint assembly [4] and welding conditions [5][6][7] and tedious programming of welding parameters [8] to produce repeatable results. With the progress and development of welding technology, automatic control is adopted to improve the welding quality monitoring and has become an important direction of the development of the welding technology.…”

Section: Introductionmentioning

confidence: 99%

Open-Closed-Loop Iterative Learning Control with the System Correction Term for the Human Soft Tissue Welding Robot in Medicine

Yang

Zhang

2020

Mathematical Problems in Engineering

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By combining manual welders (with intelligence and versatility) and automatic welding systems (with accuracy and consistency), an intelligent welding system for human soft tissue welding can be developed in medicine. This paper presents a data-correction control approach to human welder intelligence, which can be used to control the automated human soft tissue welding process. Human soft tissue welding can preconnect the excised tissue, and the shape of the tissue at the junction ensures the recovery of the operative organ function. This welding technology has the advantages of rapid operation, minimal tissue damage, no need for suture materials, faster recovery of the mechanism and properties of the living tissue, and the maintenance of the function of the organs. Model of the welding system is identified from the data; an open-closed-loop iterative learning control algorithm is then proposed to improve the tracking accuracy of the system. The algorithm uses the tracking error of current and previous to update the control law. Meanwhile, to further improve the accuracy under the conditions of external interference, a system correction term is added to the proposed ILC algorithm, which can be adjusted according to the system’s errors and output and improve the capability of the target tracking greatly. A detailed convergence analysis for the ILC law has been given. Simulation results verify the feasibility and effectiveness of the proposed method for GTAW control tasks.

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“…Also, Lee and Nam (2018) discussed Weibull distribution about Vickers hardness of Al2O3/SiC composite depending on the SiC concentration. Park et al (2018) studied about Weibull analysis to shear strength of resistance welded ball studs.…”

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confidence: 99%

Weibull statistical properties for Rockwell hardness of Incoloy 825 at different heat treatment temperatures

Nam

Son

2020

IJSI

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PurposeIn this study, the Incoloy 825 alloy was hot-forged 90% by open die forging, and the Rockwell hardness was measured by change of solution treatment temperature and aging time. The Rockwell hardness was analyzed by the Weibull statistics.Design/methodology/approachThe hot forging process generally involved heating to 1,423 K, to make grain size smaller than required grain size of 50 µm of the Incoloy 825 alloy. Thereafter, after a certain time, a forging ratio of 90% was obtained with a 5,000 ton press. At this time, the finish forging temperature was 1,173 K. To investigate the effect of solution treatment temperature, the material was maintained at 973, 1,073, 1,173 and 1,273 K for 1 h and then water-cooled. To investigate the effect of aging time, the material was water-cooled after holding for 1, 5, 10 and 30 h at 973 K.FindingsThe amount of precipitate increased with aging time, and the size of precipitate became larger. The lower the solution treatment temperature, the longer the aging time, and the Rockwell hardness increased. Shape parameter of solution-treated material increased with increasing temperature, but decreased sharply at 1,273 K. The scale parameter decreased. Shape parameters and the scale parameters of the aging treatment material increased, according to increasing of aging time.Originality/valueThe effect of heat treatment on microstructure and Rockwell hardness, in Incoloy 825 alloy with hot forging of 90% grain size increased and precipitates decreased with increasing solution treatment temperature, precipitate increased and precipitates' size increased with increasing aging time at 973 K. Shape parameter increased but scale parameter decreased. Shape parameters and scale parameters of the aging-treated material increased.

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Shear strength of ball studs according to the resistance welding conditions & reliability testing based on the weibull distribution function

Cited by 6 publications

References 5 publications

Failure analysis and countermeasures of the SCM435 high-tension bolt of three-step injection mold

Failure analysis and countermeasures of the SCM435 high-tension bolt of three-step injection mold

Open-Closed-Loop Iterative Learning Control with the System Correction Term for the Human Soft Tissue Welding Robot in Medicine

Weibull statistical properties for Rockwell hardness of Incoloy 825 at different heat treatment temperatures

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